Rotary fluid motor or pump



Feb. 14, 1950 A. z. RICHARDS, JR

ROTARY FLUID MOTOR 0R PUMP 2 Sheets-Sheet 1 Filed March 1, 1946 Feb. 14, 1950 A. z. RIcHARDs, JR

ROTARY FLUID MOTOR 0R PUMP 2 sh88ts s et 2 Filed March 1, 1946.

BI] Wm 8M2 Patented Feb. 14, 1950 UNITED;

sTATEs PATENT OFFICE This invention relates to fluid impelling .or fluid driven mechanisms, using a non-compressible fluid such as water, oil or the like, and it has particular reference to hydraulic motors and pumps of the constant flow and positive fluid displacement type. It is the principal object of the invention to provide a simplified mechanism of the type above mentioned which will operate with high efliciency at high speed as a motor and as a pump and which may be used as the one or as the other mechanism without substantial change as regards construction or as regards efficiency.

A further object of the invention consists in providing a pump or motor of the above-mentioned type having rotary pistons and an abutbeing taken along the line -0 of Figure 1. and

ment rotor operating without friction and consequent wear between each other, maintaining a tight seal between the admission or pressure section and the dischar eor delivery section of the mechanism. A further object consists in providing a hydraulic motor having a high starting torque and capable of movement in two directions upon change of the direction of flow.

Further objects will be made apparent in the following detailed 1 specification.

The accompanying drawings illustrate one embodiment of the invention. It is however to be understood that the description of one embodiment in more-or-less specific terms is not to he understood in a limitative sense. The invention is described by referring to the principles on which the specific construction illustrated is based and these principles enable experts skilled in the art to construct other embodiments. These other embodiments as far as included in the annexed claims are therefore not to be considered as a departure of but are part of the invention.

In the accompanying drawings,

Figure 1 is an elevational side view of the hydi'aulic mechanism,

Figure 2 is an elevational front view,

Figure 3 is an elevational side view of the gear carrying side,

Figure 4 is a perspective view of the piston carrying rotor,

Figure 5 is a perspective view of the abutment rotor,

Figure 6 is a sectional elevational view of a modification of the piston carrying rotor and of a portion of the adjacent casing,

Figure 7 is a sectional elevational view of the hydraulic mechanism, the section being taken along a plane passing through line '|--'I of Figure 2,

Figure 8 is a sectional plan view, the section being a horizontal section taken along theline 8-8 of Figure '1 and passing through the abutment rotor,

Figure 9 is'a sectional plan view, the section passing through the piston carrying rotor, and

Figure 10 is a front view of a modification of. 'the piston carrying rotoron its shaft.

Referring first to Figure 7, it is seen that the hydraulic motor or pump comprises a casing ll with three cylindrical compartments ll, l2, it, two of them II, l2 accommodating rotors l4, I! provided with pistons,'while the centralportion I 3 accommodates an abutment rotor l6.

Each piston rotor in the example shown con-'- sists of a cylinder I! provided with a number of vanes or blades I8, (Figures 4 and 6) two vanes being shown in the drawing. It is however, to be understood that the number of vanes is to be selected in accordance with the size, the rotational speed and the design in general and therefore is variable.

The blades or vanes of each rotor rotate within the cylindrical compartment "or l2 housing the rotor, without touching the walls of the same, a very small clearance being left between the rotating vane and the walls of the compartment.

The abutment rotor l6 comprisesva substantially cylindrical body 20 with a number of recesses 2 I, three being shown in the example illustrated. The number of recesses is dependent on the rotational speed, on the number of rotors and of vanes with which the abutment rotor has to cooperate and on the design, especially on the angular speeds of the cooperating parts.

Behind the central compartment 13 a communication channel 22 is arranged which joins the two compartments II and -I2.

Moreover, the casing Ill is provided with an inlet opening 24 and an outlet opening 25, for admitting the fluid into the compartments l2 and II respectively. The openings may be provided with means such as screw threads'fl which per- 'mit connection with admission and discharge pipes 28, 29 respectively.

The casing I II is preferably open at one end and is closed by means of a cover plate 30 screwed down and made fluid-tight by means of screws 3| and a gasket (not shown).

Each rotor l4, l5 and I6 is mounted on a shaft 33, 34, 35 held in suitable hearings in the housing l0 and the cover 30 respectively. The shafts 33, 34 are provided with gear wheels 36, 38 which are meshing with a central gear wheel 40 on shaft 35.

The gear wheels have to maintain the required connection and relation between the rotational speeds of the two piston rotors and the abutment rotor. The first requirement consists in the condition that the circumferential speeds of the rotors at the points at which they touch be equal, so that perfect rolling movement without sliding movement between the piston carrying rotors and the abutment rotor occurs.

A further requirement consists in such an arrangement and design of the recesses 2| provided in the abutment rotor l 6 that the blades or vanes I 8 may pass freely and without touching the abutment rotor, while the cylindrical surfaces l1 and 20 respectively of the piston rotor and abutment rotor roll upon. each other without slidin or gliding movement. The cylindrical surface 20 of the abutment rotor is in permanent rolling contact with one or the other or both of the piston carrying rotors at all times thus providing a, continuous tight seal between inlet opening 24 and outlet opening 25. The rolling contact between the surfaces of the abutment rotor and any one piston carrying rotor will be interrupted during the passage of a vane or blade i8. but the seal will be maintained by the opposite piston carrying rotor which is in contact with the abutment rotor. In this way each piston carrying rotor cooperating with the central abutment rotor alternately maintains the seal while its oposite is accomplishing the passage of a blade. The seal may be maintained between metallic surfaces of the rotors which are in direct contact, as illustrated in Figure'l. To provide a better sealing contact the modifications illustrated in Figures 6 and may be used according to which surfaces of the piston nomes rolling contact with the point so that no back leakage can occur during the e tire cycle.

Assuming the mechanism to operate as a pump it will be clear that the rate of flow through it will always remain constant, when the rotors rotate with a constant speed. However, the pressure in the space A behind the rotors, will permanently fluctuate between high and low. A given angular displacement of the main shaft will therefore displace a certain amount of liquid within the pump which is always the same.

Assuming the mechanism to operate as a hydraulic motor a given volume of liquid under pressure will produce a certain angular displacement carrying rotors are covered with a resilient lining described mechanism the size and shape of the recesses in the abutment rotor is designed to allow the blades to pass without coming into contact with the walls of the recesses. when the mechanism, however, is used for special purposes andin particular in the case of a hydraulic motor a modification may be preferable, according to which the back of the blade or vane I8 is provided near its end with a flat sealin strip (Figures 6 and 10) made of leather or of a synthetic composition suited for this purpose. The size and shape of. the recesses are so chosen as to provide adequate clearance from the blade with attached sealing strip. The leather stri however, does not actually touch the walls of the recess while passing through the same.

When the blades or vanes are rotating within 'the cylindrical compartments II and I2 housin the rotors the sealing strip is held tightly against the compartment wall by the pressure in the chamber behind the piston if said strip is properly arranged. In this way a complete seal is maintained automatically.

The sealing strip may be replaced as soon as it is worn out.

In the example illustrated, two rotors II and I! each provided with two vanes or blades ll, cooperate with one abutment rotor. The blades of the two rotors are arranged at right angles to each other, and the ratio of the transmission between the abutment rotor and each one of the piston rotors is 1%:1. In this way an abutment rotor with three recesses is capable of cooperating with of the rotating elements, or, in other words, the motor is operating with positive displacement of the fluid.

It will be' seen from the above that the mechanism, as described, has no reciprocating or sliding parts which might cause vibration and limit the sp edat which it has to be operated. It eliminates friction and wear at all vital points and permits to obtain unusually large piston displacement relatively to its exterior overall dimensions when compared with other known positive displacement rotary hydraulic pumps or motors. High speeds are permissible with the described mechanism even when synchronizing gears have developed or are provided with excessive play, as this mechanism does not require absolute synchronization of its rotary parts, a requirement which has to be observed most strictly in all known cases of rotary engines with abutment rotor arrangements. A the piston vanes or blades pass through the recesses of the abutment rotor without actual contact no exact fitting of the rotating members is required. A considerable margin as regards play between the synchronizing goals is therefore left.

The mechanism when used as a motor during the starting phase operates under the full available fluid pressure. The starting torque is therefore at its maximum. This is a great advantage over most other hydraulic motors. Moreover, the motor clearly can be reversed as regards direction of rotation .if the flow of the liquid'is rcversed.

The arrangement according to the invention may be used in many ways. The arrangement is usable as a pump for all purposes, as it is well adaptable for nearly every type of pump installation operating with non-abrasive liquids.

The special advantages and properties of the arrangement make it, however, suitable for several special purposes, for which hitherto-special constructions had to be provided.

One of these special uses in the metering or dispensing'of measured quantities of fluids, such as oil, gasoline or the like. Each revolution of the shaft delivers a given quantity or volume of liquid and therefore the liquid may be dispensed by counting the number of revolutions of the driving shaft.

Another special application is the 'use pf the arrangement as a hydraulic control motor for operating other machinery equipped with a hydraulic control system in which the hydraulic motor according to the invention drives the steering or master control mechanism. The motor according to the present invention is particularly suitable for this purpose because of, its high starting torque and its faculty to reverse.

The mechanism may be used with great advantage in the special field of hydraulic power transmission. The practical application of hydraulic energy to the transmission of mechanical power requires positive displacement pumps and motors of high efilciency to make speed reducers difierential, high ratio and variable speed transmission, etc. Motors and pumps according to the invention are therefore specifically adapted for the purpose in question. Conventional details such as packing around the shaft, gaskets and other conventional elements have not been illustrated or described, although they are used for. good operation.

It may finally be emphasized that it will be clear from the above specification that it is the principle according to which the hydraulic motors and pumps are built which constitutes the principal part of the invention, while the constructive details may be changed in many ways.

I claim:

1. A rotary motor or pump mechanism for noncompressible liquids with a constant rate of flow and with a constant displacement volume comprising a casing provided with an inlet and outlet channel, piston rotor compartments in communication with a single abutment rotor compartment, one of said :piston rotor compartments being in communication with the inlet channel and another communicating with the outlet channel, rpiston rotors provided with a cylindrical drum and with piston blades projecting therefrom within said piston rotor compartments, means for rotating them at an equal speed, the blades during rotation sliding along the compartment walls and subdividing the said compartments, an abutment rotor consisting of a drum in sealing contact with the drums of the piston rotors provided with recesses for the passage of the piston blades, means for rotating the abutment rotor, and a separate flow channel by-passing the abutment rotor compartment and connecting the piston rotor compartments in communication with the inlet and outlet channels respectively, for moving the non-compressible fluid continuously by the rotating pistons from the compartment connected with the inlet channel through the flow channel into the compartment connected with the outlet channel.

2. A rotary motor or pump mechanism for noncompressible liquids with a constant rate of flow and a constant displacement volume, comprising a casing with three substantially cylindrical compartments, one of said compartments being an abutment rotor compartment in communication with the other compartments, the latter being piston rotor compartments, an admission and a discharge channel in said casing, each connected with one side of the piston rotor compartments respectively, an internal flow channel within said casing leading around said abutment rotor compartment from the piston rotor compartment connected with the inlet channel to the piston rotor compartment connected with the outlet channel, a substantially cylindrical abutment rotor in said abutment rotor compartment, piston rotors in said .piston rotor compartments cooperating with the same abutment rotor and provided with cylindrical drums in sealing contact withthe cylindrical abutment rotor and with blades sliding along the cylindrical compartment walls, means for rotating said piston rotors at equal rotational speed and means for rotating said abutment rotor with a rotational speed proportional to the rotational speed of the piston rotors, each piston rotor compartment during rotation of the piston rotor being subdivided by the blades of the piston rotor and by the sealing contact with the abutment rotor into sections. one of said sections being always in communication with the inlet and outlet channel respectively and the other section being in communication with the internal flow channel connecting the piston rotor compartments.

3. A rotary motor or pump mechanism for noncompressible liquids as claimed in claim 2, wherein the piston blades are provided with pliable contact strips fixed near their ends, adapted to have their ends pressed against the compartment walls by the pressure behind the piston blade.

4. A rotary motor or pump mechanism for noncompresslble liquids of the type having a constant rate of flow with a constant displacement volume proportional to a given angular movement, comprising a casing provided with an admission and discharge channel, two substantially cylindrical piston rotor compartments in said casing connected on one side with the inlet and the outlet channel respectively, a piston rotor in each piston rotor compartment having a cylindrical drum smaller than said compartment and projecting piston blades in operative sealing and sliding contact with the compartment walls, said piston rotors having an identical number of blades, the projecting blades of one rotor in one compartment being arranged at a predetermined angle to the projecting blades of the rotor in the second compartment, means for maintaining said piston rotors in their above named relation and for rotating them at equal constant speed, a further cylindrical abutment rotor compartment between the aforesaid twopiston rotor compartments opening into and connecting said compartments and housing a cylindrical abutment rotor in sealing contact with the cylindrical drums of the piston rotors and provided with recesses for the passage of the piston blades, a channel like compartment leading around the abutment rotor compartment and connecting the piston rotor compartments at sides of said compartments opposite to those connected with the inlet and outlet channels, said channel like compartment connecting the piston rotor compartments being of such dimensions as to keep a constant displacement volume flowing between the blades of the two piston rotors during rotation of the. same at a constant rotational speed with a constant rate of flow through said channel like compartment and through the inlet and outlet channels respectively.

5. A rotary motor or pump mechanism for noncompressible liquids as specified in claim 4, wherein the cylindrical parts of the piston rotors are covered with a rubber sheet.

- ALBERT Z. RICHARDS, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 65,992 Bazin June 25, 1867 655,198 Code Aug. 7, 1900 935,079 Wheeler Sept. 28, 1909 964,754 Chader, et al July 19, 1910 1,037,455 Diefenderier Sept. 3, 1912 2,309,443 Cuthbert Jan. 26, 1943 FOREIGN PATENTS Number Country Date 88,253 Switzerland Feb. 16, 1921 185,805 Germany 1905 793,304 France Nov. 16, 1935 

